12v electric pressure pumps are often used in caravans. Lots for sale on ebay.

I have an electric pump in the tender of my Columbia. It works off a small 12v battery and the working pressure is 140psi. I purchased it off eBay. The pump sits under the water tank in the tinder and the battery just behind the tank. Works very well.

They are not the same sort of pump as used in the UK. Our pumps are submersible in a 40 litre barrel. I have one fitted to my driving trolley for topping up the saddle tank on the loco but it would not have anywhere near enough power to overcome boiler pressure.

try in tank car fuel pump can del 80 to 90 psi

I wonder what it's like to shower under a 10 bar pump.

Just because it says Caravan Camping Boat doesn't mean it's really suitable.

" what it's like to shower under a 10 bar pump" These are low volume pumps and no problem if you use the correct shower head.

Like the multi-purpose nozzles that you use on a garden hose. Select a single hole for a high pressure jet of water or one with many holes for a soft shower. The pressure in the water supply to the house remains high but the pressure at the nozzle discharge is lower because of the larger surface area.